Science students performed four investigations using many different solutions. In each investigation, the students mixed two of the solutions. A table of their observations is shown below.
1. The temperature of the solutions increased after they were combined.
2. The solution mixed together without any noticeable change in temperature.
3. A solid predicate formed after the solutions were combined together
4. The temperature of the solution decreased after they were placed together and bubbles were formed.
During which investigation did the solutions least likely react chemically?
A. Investigation 1
B. Investigation 2
C. Investigation 3
D. Investigation 4